1. Field of the Invention
The present invention relates to a modular electronic assembly and more particularly to an improved plastic modular casing which includes a battery holder and a substrate holder in an integral unit.
2. Description of the Prior Art
The inventors of the present invention have previously filed an application, Ser. No. 638,312, on Dec. 8, 1975, entitled An Improved Battery Holder in which they have disclosed an improved battery holder which allows a modular electronic assembly to operate while it is outside its casing. One of the features of this invention is that the casing did not have to be formed from a conductive material.
Presently all other modular electronic assemblies are inserted into metal casings which serve not only as battery holders, but also as conduction paths for the electronic circuits in the modular electronic assemblies. Each modular electronic assembly includes a pair of 11/2 volt, one cell batteries, a substrate with a printed circuit placed thereon, an electro-optical display which is mounted on the substrate and an integrated circuit chip which is mounted on the substrate and electrically connected to the electro-optical display and the pair of batteries through the printed circuit. U.S. Pat. No. 3,838,568, entitled Electronic Watch Movement Mounting and Connection, issued to Rudolf F. Zurcher and I. Benjamin Merles on Oct. 1, 1974, sets forth a description of a modular electronic assembly which is inserted in a metal casing. The modular electronic assembly includes a substrate that is mounted on a battery holder in such a manner that it may move in a lateral direction across the top surface of the battery holder. At least one of the springs connects itself to the integrated circuit chip and to the metal casing so that when a pushbutton switch is depressed an electrical signal can travel along a conduction path through the metal casing from one of the batteries. It is therefore essential that the casing be metallic or conductive in order for this electronic modular assembly to operate.
The above described modular electronic assembly is inoperable when it is outside the metal casing because there is no conduction path through which the electrical signal can travel from the battery to the integrated circuit chip. Generally, the metal casing includes a ring having a front edge adapted to receive a viewing element such as a watch crystal or a watch glass, and to hold that viewing element in place, and a back element adapted so that it is mechanically coupled to the ring adjacent the back edge thereof. The modular electronic assembly is placed in the ring between the viewing element and the back element, which are both secured at the front edge and the back edge of the ring respectively.
U.S. Pat. No. 3,846,971, entitled Package For Electronic Watch Movement, issued to Ernest C. Ho, Karl H. Reissmueller, and Richard J. Belardi, on Mar. 21, 1973, and teaches a cover positioned over portions of a substrate which has an integrated circuit chip and a display device with a cover being substantially flat so that it extends over the substrate and has downturned falanges along the edge of the cover and also the cover has a transparent window positioned over the display device with the rest of the cover being optically opaque. The casing taught in this patent must also be a conventional metal casing.
In all of the above-described module frames the batteries are disposed beneath the substrates on which the integrated circuit chips are mounted thereby resulting in a relatively thick electronic modular watch. Furthermore, these modular electronic watches are all placed in standardized casings, the external shapes and the colors of which are extremely limited.
Finally, many individuals are allergic to metals and cannot comfortably wear most electronic watches presently available.